The present invention relates to the recovery of metal cations from aqueous effluent solutions, especially aqueous effluent solutions from metal finishing plants, by solvent extraction and stripping techniques.
The removal of copper, nickel and chromium from the aqueous effluent of a metal finishing plant is known. In a typical known system, the metals are recovered by short bed ion exchange. Periodically, the ion exchangers are regenerated to yield a concentrated metal salt solution which is recycled to the appropriate plating bath. "Copper, Nickel, and Chrome Recovery in a Jobshop to Eliminate Waste Treatment and Sludge Disposal", Michael Dejak et al, Hazardous Waste & Hazardous Materials, Vol. 4, No. 3, 1987. See U.S. Pat. No. 4,186,174.
There is still a need, however, for other methods of removing metal cations from metal finishing plant effluent which are efficient and cost-effective.